Dentin is the substance between enamel or cementum and the pulp chamber. It is secreted by the odontoblasts of the dental pulp. The formation of dentin is known as dentinogenesis. The porous, yellow-hued material is made up of 70% inorganic materials, 20% organic materials, and 10% water by weight.
Medical Definition of metaplasia. 1  1: transformation of one tissue into another metaplasia of cartilage into bone. 2  2: abnormal replacement of cells of one type by cells of another.
The metaplasia is commonly associated with the other types of cell disorders such as heteroplasia or dysplasia but they are really totally different from one another. Having this kind of disorder is not carcinogenic, but the abnormalities it can bring can also harm the person by having other types of medical problems.